After monitoring the daily schedule of the children for several months, Belton came to the conclusion that their lack of imagination was, at least in part, caused by the absence of “empty time,” or periods without any activity or sensory stimulation. She noticed that as soon as these children got even a little bit bored, they simply turned on the television: the moving images kept their minds occupied. “It was a very automatic reaction,” she says. “Television was what they did when they didn’t know what else to do.”

The problem with this habit, Belton says, is that it kept the kids from daydreaming. Because the children were rarely bored — at least, when a television was nearby — they never learned how to use their own imagination as a form of entertainment. “The capacity to daydream enables a person to fill empty time with an enjoyable activity that can be carried on anywhere,” Belton says. “But that’s a skill that requires real practice. Too many kids never get the practice.”

But television isn’t the default network that Lehrer is referring to:

Every time we slip effortlessly into a daydream, a distinct pattern of brain areas is activated, which is known as the default network. Studies show that this network is most engaged when people are performing tasks that require little conscious attention, such as routine driving on the highway or reading a tedious text. Although such mental trances are often seen as a sign of lethargy — we are staring haplessly into space — the cortex is actually very active during this default state, as numerous brain regions interact. Instead of responding to the outside world, the brain starts to contemplate its internal landscape. This is when new and creative connections are made between seemingly unrelated ideas.